Mixed esters of fatty acids



ize at higher atmospheric temperatures.

Patented May 10, 1949 2,469,446 1 MIXED ns'rnns or FATTY ACID Frank A. Strauss, New Brighton, Staten Island, N. Y., minor to E. F. Drew 8; 00., Inc., New York, N. Y., a corporation of Delaware No Drawing. Application August 8, 1944, Serial No. 548,626

Claims. (Cl. 260-4105) 1 The present invention'is directed to a composition of matter. more particularly to a composition containing mixed esters of certain fatty acids.

The present application is a continuation-in-part of my copending application Serial No. 367,672, filed November 28, 1940, entitled Plastic compositions containing caprylic acid esters, Patent No. 2,372,522, dated March 27, 1945. Said copending application is, in turn, a continuation-inpart of abandoned application Serial No. 199,673, filed April 2, 1938, and entitled Esters of caprylic acid and compositions containing the same.

In the prior art, various esters have been used as plasticizers for resinous and similar compositions for various uses, such as in molding and for film-forming purposes. Among such plasticizer compositions was the stearic acid ester of triethylene glycol, which was incorporated in nitrocellulose. Such a product had the disadvantage that the solubility thereof in nitrocellulose was rather low and if any substantial quantity of the plasticizer was added to the nitrocellulose, there was a tendency for the plasticizer to separate out and produce a frosty, non-transparent appearance. Therefore, the plasticizing value of the material could not be utilized. It has also been proposed to provide a plasticizer consisting of the diethylene glycol ester of a lower fatty acid such as acetic or propionic. low melting points and have a tendency to vapor- As a result, compositions plasticized therewith tended to become brittle on ageing because of the gradual loss of plasticizer due to the appreciable vapor tension thereof. these compounds is relatively poor and compositions made therewith subject to contact with water or water vapor tend to deteriorate.

The present invention is intended and adapted to overcome the difficulties inherent inplasticizers previously used and to provide a composition which is a substantially neutral mixed ester which may be incorporated in various resins and similar compounds to exert plasticizing effects.

It is also among the objects of the present invention to provide a composition which is compatible in large amounts and over a wide range with substances plasticized therewith.

It is still further among the objects of, the present invention to provide a composition having plasticizlng properties which is substantially non-volatile, has no tendency to crystallize,,andwhich becomes a permanent part of the plasticized composition under all conditions of service.

In practicing the invention there are provided Also, the water resistance of 3 Such compounds have esters of fatty acids having 8 and 10 carbon atoms, namely, caprylic and capric acids. A mixture of such acids is esterifled with polyalkylene glycols such as diethylene, triethylene and propylene glycols. The esteriflcation is complete so asto form substantially neutral esters. The fatty acids incorporated in the composition may be natural fatty acids, synthetic acids and isomers thereof.

There-is usually present in the composition, in addition to the caprylic and capric acids, a lower fatty acid such as caproic, having 6 carbon atoms, or a higher acid such as lauric acid,'having 12 carbon atoms, or both. Although small amounts-of the latter two acids are usually present, the beneficial effect thereof in providing plasticizing compositions is substantial.

The esters of the present invention do not have the disadvantages of the esters of higher fatty acids in that they are compatible in practically all proportions with various base compositions. They do not have the disadvantages of the esters of lower fatty acids in that they are non-volatile, are permanent in the compositions and have better water-resistance. Because they consist of mixed esters, there is no tendency thereof to crystallizeand their solubility in various solvents, resins, and the like, is excellent.

The following are specific examples of a few of the many compositions which may be made in accordance with the present invention:

Example I I The soap-obtained in the alkali refining of co- 'coa'nut oil is treated with sulphuric acid and split in the usual fashionwith Twitchell reagent. The free fatty acids formed in the reaction are separated and then fractionated by distillation to give a low boiling fraction having approximately the following composition:

Per cent Caproic acid 2- 5 Capryli'c acid 62-68 Capric acid 28-32 Laurie acid 2- 5 so glycol in a suitable vessel. The mixture is heated for about two hours with a gradual rise in temperature from 145 C. to a maximum of 220 C. at the end of the operation. The reaction mixture is agitated vigorously during the heating and carbon dioxide is introduced into the vessel, which may be at atmospheric or higher pressure.- If desired, the esterification may be conducted in a partial vacuum. When the reaction is substantially complete, the mass is subjected to vacuum distillation to remove excess of fatty acid or of glycol or both. The crude mixed esters are refined by the usual treatment with alkali, washing, bleaching with fullers earth, and activated carbon, and deodorized in a vacuum at '70-125 C.

The resulting product has a saponification number of about 310 and the free fatty acids calculated as oleic being about .04. The odoris mild and pleasant. The product is approximately water-white, is quite stable and does not have a tendency to become rancid.

Example 11 A mixture is made of 300 grams of'caprylic acid obtained by the fractional distillation of the mixed fatty acids of cocoanut oil and containing approximately 97% of caprylic acid with very minor amounts of other fatty acids of cocoanut oil, mostly capric acid, and 100 grams of diethylene glycol. The mixture is placed in a container, heat is applied, and a gentle stream of carbon dioxide is passed through the same. The temperature is gradually raised over a period of three hours up to about 270 0., 'at which point it is held for several hours while causing a stream of carbon dioxide to pass through the same, in order to distill of! any excess of fatty v repeated if necessary until the color is discharged.

The refined product, which is a pale limpid oil, is substantially insoluble in water, but is miscible with practically all the usual lacquer solvents and diluents in all proportions. One part of the refined product is mixed with three parts of low viscosity nitrocellulose and is thoroughly incorporated in the same by conducting the mixing on hot rolls.

Example I II There is provided 125 grams of a mixture of diethylene glycol and triethylene glycol in equal proportions. To this is added 300 grams of a fraction of distilled'cocoanut oil fatty acids, composed principally of about 85% caprylic acid and small amounts'of adjacent acids, namely capric and lauric acids, and having an acid number of about 383. The mixture is heated in the presence of a gentle stream of carbon dioxide for over three hours, the temperature being gradually increased until about 2'70 'to 275 C. is

reached, at which temperature the mixture is held for about one hour while passing a current of carbon dioxide through the same. The mixture is purified as stated above, and the properties of the product are quite similar to the product of Example I.

A mixture is made of 40 parts by weight of this ester with 60 parts by, weight of low viscosity ethyl cellulose (6T5 sec). Theingredients are heated and compounded in a suitable mill until the mixture is uniform.

about of caprylic acid and the remainder capric acid. A reaction is caused to take place following the procedure set forth in Example II. 3 parts by weight of the mixed ester is incorporated in 7 parts by weight of a polyvinyl resin. Specifically, the resin used is of the aldehyde modified polyvinyl acetate, and commonly termed vinyl acetal resin, wherein a condensation was caused to take place between polyvinyl alcohol and butraldehyde. The mixture is formed on hot rolls and is extruded into sheets for use.

The mixed esters of the present invention are compatible with nitrocellulose both in solution and in the resulting films or molded productsin all proportions up to at least 3 parts of plasticizer to 2 parts of the nitrocellulose. There is no tendency for a separation of the plasticizer even when the composition is baked at 200 F. The compositions are ihert to atmospheric oxidizing conditions and are not decomposed or changed by light, although sunlight has a tendency to bleach the mixed esters. They have strong softening action and a low specific gravity.

This material is particularly adapted for use in flexible coatings. For these'purposes it has the virtues of a true solvent plasticizer for nitrocellulose, compatibility, chemical inertness and neutrality, without the tackiness which sometimes results when large quantities of solvent plasticizer are used to get a flexible film. At the same time, it exhibits the good qualities of the plasticizers of the vegetable oil type, giving flexible pliable films without tendency to tackiness, yet not having the bad odor, poor color, susceptibility to oxidation and sweating tendencies which many of'these oil plasticizers often have. 1

Although I have described my invention setting forth several specific embodiments thereof,

' it will be appar nt that various changes in the detailsmay be ple and polymerized, and various higher glycols than propylene glycol may be used. The reaction may be conducted in any suitable manner as is well known. The proportions of the several acids in the mived esters may be varied within wide limits, it being essential that the caprylic acid be the major constituent and the capric acid be next in amount. The proportions of these two acids may vary from parts of caprylic to 3-35 parts ofcapric. acid. Other resins and plastics may be plasticized with' these compositions, as for instance the phenol formaldehyde, urea formaldehyde, alkyd, acrylate, and various other resinous materials. The proportions of the mixed esters which may be introduce into the compositions may vary widely.

These and other changes in the details of the invention may be made within the spirit thereof and the scope of the invention is not to be limited except by the character of the claims appended hereto.

What I claim is:

l. A composition of matter consisting of the substantially neutral mixed esters of a fully esterified polyalkylene glycol taken from the class consisting of ethylene and propylene glycols with a mixture of fatty acids consisting essentially of caprylic and capric acids, the relative proportions of caprylic to capric acid being 62-97% of caprylic to 32-3% of capric, the remainder of said acids being lauric and caproic in total amount not over 10%.

2. A composition of matter consisting of the substantially neutral mixed esters of a fully esterified polyalkylene glycol taken from the class consisting of ethylene and propylene glycols with a mixture of fatty acids consisting essentially of caprylic and capric acids, the relative proportions of caprylic to capric acid being 62-68% caprylic and 28-32% capric.

3. A composition of matter consisting of the substantially neutral mixed esters of a fully esterified polyalkylene glycol taken from the class consisting of ethylene and propylene glycols with a mixture of fatty acids consisting essentially of capryl ic and capric acids, the relative proportions of caprylic to capric acid being 100 to about 15.

4. A composition of matter consisting of the substantially neutral mixed esters of a fully esterified polyalkylene glycol taken from the class consisting of ethylene and propylene glycols with a mixture of fatty acids consisting essentially of caprylic and capric acids, the relative proportions of caprylic to capric acid being about 2 to 1.

5. A composition of matter consisting of the substantially neutral mixed esters of a fully esterified polyalkylene glycol taken from the class consisting of ethylene and propylene glycols with a mixture of fatty acids in about the following proportions:

Percent Caproic acid 2-5 Caprylic acid 62-68 Capric acid 28-32 Laurie acid 2-5 FRANK A. STRAUSS.

REFERENCES CITED The following references are of record in the file of this patent: 

